Regulatory reform and market efficiency: The case of Indian agricultural commodity futures markets

We present the results of two efficiency measures that include intraday return predictability measure based on order imbalance and measures of several variance ratio tests on intraday subsamples of nine major Indian agricultural commodity futures (castor seed, cotton oil cake, rape mustard seed, soybean, refined soya oil, crude palm oil, jeera, chana, and turmeric) quoted in the National Commodity and Derivatives Exchange (NCDEX). We perform the efficiency measures on five subsamples with holding periods of 5, 10, 15, 30, and 60 min over two sample periods following the announcement of the merger between the Forward Market Commission (FMC) and Securities Exchange Board of India (SEBI). We compare results of tests of weak-form market efficiency of futures markets between two periods (pre-merger period and post-merger period). Our results confirm that Indian agricultural commodity futures markets continue to remain inefficient in the short-term during both pre-merger and post-merger periods. Based on these findings, it is likely that profitable trading strategies in the short intraday intervals will be available for traders and market participants during post-merger period. Thus, regulators must focus more on policy initiative so as to enhance market quality in order to address such inefficiencies in Indian commodity futures markets.     

Rank tests for price convergence in Australian beverage markets

This article examines the price convergence of beverage products within Australia in order to assess the efficacy of intranational cross-border movements of products under the Australia’s Mutual Recognition Agreement. Since the cointegrating relationship between product prices may not be exact or linear, we adopt the rank tests for analysis which do not require prior knowledge and specification of the linear or nonlinear functional form. Our results validate the price convergence of all beverage products within Australia, with the exception of a few regions in the milk market. Furthermore, a subset of the cointegration relationships exhibits nonlinear long-run price co-movements.     

The effect of aviation responses to the control of imported COVID-19 cases

The outbreak of the COVID-19 pandemic has a lasting and unprecedented negative impact on the global aviation industry. While countries such as China have successfully curbed the domestic outbreak of the virus with various restrictive and preventive measures, the challenge of avoiding imported cases remains. More importantly, it is still unclear to what extent these implemented aviation emergency responses have effectively mitigated the transmission risk of the virus. This paper provides an empirical assessment of aviation responses to the control of imported COVID-19 cases, with a focus on the following three strategies: the “circuit breaker” policy, the “negative Nucleic Acid testing (NAT)”, and the “double negative tests” requirement. Non-recursive structural equation models (SEM) with latent variables were applied to detailed international flight data and individual epidemic survey data of Guangzhou, China, between May 1 and November 30, 2020. The results show that the “double negative tests” measure has a positive effect on eliminating the number of SARS-CoV-2 carriers, while the effects of single “circuit breaker” and its co-intervention with “negative NAT” are conterproductive. This study provides important implications to civil aviation agencies in regard to medium and long-term risk control of imported cases. Specifically, although the circuit breaker mechanism was designed to target on the risk control of imported COVID-19 cases, it may be more effective to carefully maintain a timely and reliable pre-boarding screening and testing to curb the number of imported cases.     

Dynamic interactions between Central European currencies and the euro

We argue that the non-euro EU currencies of Central European countries have moved increasingly together with the euro in foreign exchange markets. To prove this point, we examine the dynamics of cross-elasticity between selected Central European currencies (the Czech koruna, Polish zloty, and Hungarian forint) and the euro exchange rates in U.S. dollar terms using daily data for the January 4, 2000 to April 5, 2019 sample period. We adopt the cross-elasticity model originally proposed and tested for the EU currencies by Orlowski (2016). To test the currency co-movements over time, we employ the Bai-Perron multiple breakpoint regression and two-state Markov switching tests. We find evidence of increasing co-movements between the Central European currencies and the euro that become particularly pronounced in times of financial distress. Co-movements of local exchange rates with the euro are also more pronounced during the euro-periphery sovereign debt crisis.     

LINEAR TREND TEST VERSUS GLOBAL TEST: A COMPARISON

For the I –sample problem, the classical global tests on treatment differences are compared with the respective trend tests both in the parametric and nonparametric case using a comparison criterion closely related to the concept of asymptotic relative Pitman efficiency.     

Evaluating employee integrity: Moral and methodological problems

This paper reviews the research on proprietary paper and pencial tests of integrity or honesty, which have effectively supplanted polygraph examinations in evaluating the moral attributes of employees and applicants. Moral integrity is a complex issue that encompasses more than conventional notions of honesty and is difficult to operationalize as a psychological trait or construct. Integrity test questions are largely derived from polygraph interrogations and the tests validated through polygraph results. The field studies reviewed and an exploratory test cast doubt on the ability of these paper and pencil instruments to meet standards of construct validity. Other studies show promise of predictive validity in some situations. Unfortunately, the research designs used to substantiate the predictive powers of integrity tests failed to hold other workplace influences constant. In light of these findings, employers are urged to exercise caution in the use of these tests until further independent research is reported because of potential infringements on privacy and equal opportunity.     

Quality control for structural credit risk models

Over the last four decades, a large number of structural models have been developed to estimate and price credit risk. The focus of the paper is on a neglected issue pertaining to fundamental shifts in the structural parameters governing default. We propose formal quality control procedures that allow risk managers to monitor fundamental shifts in the structural parameters of credit risk models. The procedures are sequential — hence apply in real time. The basic ingredients are the key processes used in credit risk analysis, such as most prominently the Merton distance to default process as well as financial returns. Moreover, while we propose different monitoring processes, we also show that one particular process is optimal in terms of minimal detection time of a break in the drift process and relates to the Radon–Nikodym derivative for a change of measure.     

Random walk and breaking trend in financial series: An econometric critique of unit root tests

The present note sheds light on several pitfalls associated with unit root tests that are overlooked by a growing volume of literature in financial economics. Specifically, several studies have confused unit root tests with the Random Walk hypothesis. Unit root tests are not designed for such a task since they aim at investigating whether a time series is difference-stationary or trend-stationary and are not, therefore, predictability tests. Secondly, we emphasize some serious shortcomings associated with the widely used unit root test developed by Zivot and Andrews [Zivot, E. & Andrews, D.W.K. (1992). Further evidence on the great crash, the oil-price shock, and the unit-root hypothesis. Journal of Business and Economic Statistics, 10, 251–270.]. In particular, we stress that results from the Zivot–Andrews test are sensitive to the methods employed to calculate the critical values and to select the maxim lag k. Furthermore, Zivot–Andrews test imposes a one time structural break in a time series; however recent studies showed that not counting for other true structural breaks may bias the results and may cause a spurious rejection of the unit root null hypothesis. Finally, we support our arguments by an empirical example based on the findings of Narayan and Smyth [Narayan, K.P. & Smyth, R. (2004). Is South Korea’s stock market efficient? Applied Economics Letters, 11, 707–710.] with regards to the efficiency of South Korean stock market. We show that contrary to what the authors claim, the KSE (KOSPI) price index is predictable, and hence the South Korean stock market is not informationally efficient.     

Regional income convergence in Indochina 1970–2015?

Real incomes have been increasing relatively fast in the Indochina region but there are still large differences in income levels between the six member countries. Based on the various sources of national accounts data, it seems that the low-income countries have experienced the highest growth rates. Time series tests of convergence, in this case catching-up to the relatively high-income level in Malaysia, confirm that Cambodia, Myanmar, Thailand and Vietnam have narrowed the income gap during the last two decades.     

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